As the others have confirmed the dealer is talking rubbish! I've got the retractable bar on. 2018 Edition.
I've towed a 2010 Lunar Clubman and a 2018 Bailey Unicorn both with Alko hitch and never had a problem. If you have the reversing camera make sure you use the 'hitch' view when reversing up to the van and it's a doddle.
When reversing the van onto the pitch release the alko clamp so that the van turns more freely and once in place apply the van brake and ease the car forward to release the pressure on the hitch, then it will unhook without making contact with the bumper